In feed milling nutrient levels there should be established both chicks need and financial circumstances and any variation of nutrient composition should be followed by a prompt answer in slaughtering performances leading to a competitive feed cost and so to a competitive final product cost with no change in chemical meat composition. Some values about carcass output and percentage of body parts in carcass were determined for this purpose using feed combination with variable parameters. Experiments were performed at S.D.E. Avicola Moara Domneasca during 56 days with 150 birds (Ross 308) divided in three treatments based of nutritive value of combined feed given (CM, C1, C2). Data that was obtained during the experiment was processed and so it was noticed that the best commercial output was obtained in the group with constant nutritive parameters (CM – 81.4 ± 0.53%) and the best breast percentage from carcass was noticed in the group with constant nutritive parameters (CM – 25.9 ± 0.94%) and the best in leg percentage was noticed in the group with variable protein (C1 – 27.7 ± 0.54%).